One of the easiest ways to detect otherwise unseen underwater pollution in our lakes and oceans is to monitor the animal life. Sometimes subtle changes in fish population can signal a greater problem that demands immediate attention. Not content to let living creatures be our canaries in the coal mine, a British firm named BMT is heading a project to create robotic fish that will monitor water quality at a fraction of the cost of human divers.

Called SHOAL fish, the aquatic robots are roughly the size of a large tuna, and are designed to move and act much like a living ocean fish. The SHOAL contain a litany of on-board censors that can detect chemical leakage and other man-made environmental hazards. One one of the robots finds something suspicious, it alerts port authorities who can quickly respond and — in theory — remove the source of the pollution.